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A136034 a(n) = smallest number k such that number of distinct prime factors of 2^k-1 is exactly n. 0
1, 2, 4, 8, 12, 20, 24, 40, 36, 48, 88, 60, 72, 150, 132, 120, 156, 144, 200, 204, 210, 180, 324, 476, 288, 300, 432, 396, 480, 360, 468, 576, 700, 504, 420, 648, 540, 660, 792, 720 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
First occurrence of n in A046800.
LINKS
PROG
(PARI) a(n) = my(k=1); while (omega(2^k-1) != n, k++); k; \\ Michel Marcus, Jan 09 2023
CROSSREFS
Sequence in context: A206350 A127405 A344932 * A243112 A230127 A059793
KEYWORD
nonn,more
AUTHOR
Artur Jasinski, Dec 11 2007
EXTENSIONS
More terms from Julián Aguirre, Feb 04 2013
a(31)-a(39) from Chai Wah Wu, Oct 03 2019
a(0) = 1 inserted by Michel Marcus, Jan 09 2023
STATUS
approved

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Last modified March 28 04:13 EDT 2024. Contains 371235 sequences. (Running on oeis4.)